create queue with QoS class, resolve #7

Author: flier

src/ffi.rs

@@ -1,6 +1,6 @@
 #![allow(missing_docs, non_camel_case_types, improper_ctypes)]
 
-use std::os::raw::{c_char, c_int, c_long, c_ulong, c_void};
+use std::os::raw::{c_char, c_int, c_long, c_uint, c_ulong, c_void};
 
 use block::{Block, BlockArguments, ConcreteBlock, IntoConcreteBlock};
 use libc::{mode_t, off_t, timespec};
@@ -42,7 +42,7 @@ pub type dispatch_io_close_flags_t = u64;
 pub type dispatch_io_interval_flags_t = u64;
 pub type dispatch_queue_attr_t = *const dispatch_object_s;
 pub type dispatch_block_flags_t = u64;
-pub type dispatch_qos_class_t = u64;
+pub type dispatch_qos_class_t = c_uint;
 
 #[cfg_attr(any(target_os = "macos", target_os = "ios"), link(name = "System", kind = "dylib"))]
 #[cfg_attr(
@@ -58,13 +58,28 @@ extern "C" {
     pub fn _Block_copy(block: *const c_void) -> *mut c_void;
     pub fn _Block_release(block: *mut c_void);
 
+    pub fn qos_class_self() -> dispatch_qos_class_t;
+    pub fn qos_class_main() -> dispatch_qos_class_t;
+
+    pub fn dispatch_queue_attr_make_initially_inactive(
+        attr: dispatch_queue_attr_t,
+    ) -> dispatch_queue_attr_t;
+    pub fn dispatch_queue_attr_make_with_qos_class(
+        attr: dispatch_queue_attr_t,
+        qos_class: dispatch_qos_class_t,
+        relative_priority: c_int,
+    ) -> dispatch_queue_attr_t;
+
     pub fn dispatch_get_global_queue(identifier: c_long, flags: c_ulong) -> dispatch_queue_t;
     pub fn dispatch_queue_create(
         label: *const c_char,
         attr: dispatch_queue_attr_t,
     ) -> dispatch_queue_t;
-    // dispatch_queue_attr_t dispatch_queue_attr_make_with_qos_class ( dispatch_queue_attr_t attr, dispatch_qos_class_t qos_class, int relative_priority );
     pub fn dispatch_queue_get_label(queue: dispatch_queue_t) -> *const c_char;
+    pub fn dispatch_queue_get_qos_class(
+        queue: dispatch_queue_t,
+        relative_priority_ptr: *mut c_int,
+    ) -> dispatch_qos_class_t;
     pub fn dispatch_set_target_queue(object: dispatch_object_t, queue: dispatch_queue_t);
     pub fn dispatch_main();
 
@@ -280,6 +295,13 @@ pub fn dispatch_get_main_queue() -> dispatch_queue_t {
     unsafe { &_dispatch_main_q as *const _ as dispatch_queue_t }
 }
 
+pub const QOS_CLASS_USER_INTERACTIVE: dispatch_qos_class_t = 0x21;
+pub const QOS_CLASS_USER_INITIATED: dispatch_qos_class_t = 0x19;
+pub const QOS_CLASS_DEFAULT: dispatch_qos_class_t = 0x15;
+pub const QOS_CLASS_UTILITY: dispatch_qos_class_t = 0x11;
+pub const QOS_CLASS_BACKGROUND: dispatch_qos_class_t = 0x09;
+pub const QOS_CLASS_UNSPECIFIED: dispatch_qos_class_t = 0x00;
+
 pub const DISPATCH_QUEUE_SERIAL: dispatch_queue_attr_t = 0 as dispatch_queue_attr_t;
 pub static DISPATCH_QUEUE_CONCURRENT: &'static dispatch_object_s =
     unsafe { &_dispatch_queue_attr_concurrent };

src/lib.rs

@@ -73,6 +73,7 @@ mod blk;
 mod data;
 #[cfg(target_os = "macos")]
 mod io;
+mod qos;
 #[cfg(target_os = "macos")]
 mod sem;
 mod time;
@@ -86,6 +87,7 @@ pub use data::{
 };
 #[cfg(target_os = "macos")]
 pub use ffi::{DISPATCH_IO_STOP, DISPATCH_IO_STRICT_INTERVAL};
+pub use qos::QosClass;
 #[cfg(target_os = "macos")]
 pub use sem::Semaphore;
 pub use time::{after, at, now, Timeout, WaitTimeout};
@@ -97,6 +99,16 @@ pub enum QueueAttribute {
     Serial,
     /// The queue executes blocks concurrently.
     Concurrent,
+    /// Attribute for dispatch queues.
+    Value(dispatch_queue_attr_t),
+}
+
+impl Drop for QueueAttribute {
+    fn drop(&mut self) {
+        if let &mut QueueAttribute::Value(attr) = self {
+            unsafe { dispatch_release(attr as *mut _) }
+        }
+    }
 }
 
 impl QueueAttribute {
@@ -105,6 +117,7 @@ impl QueueAttribute {
         match *self {
             QueueAttribute::Serial => DISPATCH_QUEUE_SERIAL,
             QueueAttribute::Concurrent => DISPATCH_QUEUE_CONCURRENT,
+            QueueAttribute::Value(attr) => attr,
         }
     }
 
@@ -115,6 +128,30 @@ impl QueueAttribute {
         // Back then, the attr for dispatch_queue_create must be NULL.
         ptr::null()
     }
+
+    /// Returns an attribute value which may be provided to `Queue::create` or `Queue::with_target_queue`,
+    /// in order to make the created queue initially inactive.
+    #[cfg(target_os = "macos")]
+    pub fn inactive(self) -> Self {
+        let attr = unsafe { dispatch_queue_attr_make_initially_inactive(self.as_raw()) };
+
+        QueueAttribute::Value(attr)
+    }
+
+    /// Returns an attribute value which may be provided to `Queue::create` or `Queue::with_target_queue`,
+    /// in order to assign a QOS class and relative priority to the queue.
+    #[cfg(target_os = "macos")]
+    pub fn with_qos_class(self, qos_class: QosClass, relative_priority: i32) -> Self {
+        let attr = unsafe {
+            dispatch_queue_attr_make_with_qos_class(
+                self.as_raw(),
+                qos_class as dispatch_qos_class_t,
+                relative_priority,
+            )
+        };
+
+        QueueAttribute::Value(attr)
+    }
 }
 
 /// The priority of a global concurrent queue.
@@ -263,6 +300,16 @@ impl Queue {
         str::from_utf8(label.to_bytes()).unwrap()
     }
 
+    /// Returns the QOS class and relative priority of the given queue.
+    pub fn qos_class(&self) -> (QosClass, i32) {
+        let mut relative_priority = 0;
+
+        let qos_class =
+            unsafe { dispatch_queue_get_qos_class(self.ptr, &mut relative_priority) }.into();
+
+        (qos_class, relative_priority)
+    }
+
     /// Submits a closure for execution on self and waits until it completes.
     pub fn sync<T, F>(&self, work: F) -> T
     where
@@ -694,9 +741,25 @@ mod tests {
         let q = Queue::create("", QueueAttribute::Serial);
         let mut num = 0;
 
+        q.sync(|| num = 1);
+        assert_eq!(num, 1);
+        assert_eq!(q.qos_class(), (QosClass::Unspecified, 0));
+
+        assert_eq!(q.sync(|| num), 1);
+    }
+
+    #[test]
+    fn test_serial_queue_with_qos_class() {
+        let q = Queue::create(
+            "",
+            QueueAttribute::Serial.with_qos_class(QosClass::UserInteractive, 0),
+        );
+        let mut num = 0;
+
         q.sync(|| num = 1);
         assert_eq!(num, 1);
 
+        assert_eq!(q.qos_class(), (QosClass::UserInteractive, 0));
         assert_eq!(q.sync(|| num), 1);
     }
 

src/qos.rs

@@ -0,0 +1,48 @@
+use std::mem;
+
+use ffi::*;
+
+/// An abstract thread quality of service (QOS) classification.
+#[repr(u32)]
+#[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
+pub enum QosClass {
+    /// A QOS class which indicates work performed by this thread is interactive with the user.
+    UserInteractive = QOS_CLASS_USER_INTERACTIVE,
+    /// A QOS class which indicates work performed by this thread was initiated by the user
+    /// and that the user is likely waiting for the results.
+    UserInitiated = QOS_CLASS_USER_INITIATED,
+    /// A default QOS class used by the system in cases where more specific QOS class information is not available.
+    Default = QOS_CLASS_DEFAULT,
+    /// A QOS class which indicates work performed by this thread may or may not be initiated by the user
+    /// and that the user is unlikely to be immediately waiting for the results.
+    Utility = QOS_CLASS_UTILITY,
+    /// A QOS class which indicates work performed by this thread was not initiated by the user
+    /// and that the user may be unaware of the results.
+    Background = QOS_CLASS_BACKGROUND,
+    /// A QOS class value which indicates the absence or removal of QOS class information.
+    Unspecified = QOS_CLASS_UNSPECIFIED,
+}
+
+impl Default for QosClass {
+    fn default() -> Self {
+        QosClass::Default
+    }
+}
+
+impl From<u32> for QosClass {
+    fn from(v: u32) -> Self {
+        unsafe { mem::transmute(v) }
+    }
+}
+
+impl QosClass {
+    /// Returns the requested QOS class of the current thread.
+    pub fn current() -> Self {
+        unsafe { qos_class_self() }.into()
+    }
+
+    /// Returns the initial requested QOS class of the main thread.
+    pub fn main() -> Self {
+        unsafe { qos_class_main() }.into()
+    }
+}